The goal of the proposed research is to develop guidelines for the prevention of esophageal adenocarcinoma. This will be accomplished by constructing and refining a Markov disease model of Barrett's esophagus which will integrate currently available short-term data to project long-term consequences. A small percentage of patients with gastroesophageal reflux disease (GERD) develop a pre-malignant metaplasia termed Barrett's esophagus, which can subsequently develop into esophageal adenocarcinoma. In response to the alarming increase in the incidence of esophageal adenocarcinoma in the last two decades, patients with heartburn or reflux symptoms are increasingly undergoing endoscopic evaluation. Patients who are found to have Barrett's esophagus are then advised to undergo endoscopic screening at regular intervals with the goal of reducing the mortality and morbidity of esophageal cancer through its early detection. More recently, epidemiologic data suggesting that non-steroidal anti-inflammatory drugs (NSAIDs) may decrease the incidence of esophageal cancer has been published. However, presently there are no long-term data defining the utility of endoscopic screening or NSAID chemoprevention for esophageal cancer. Using the methodologies of decision analysis and disease modeling, the research described in this proposal will carry out the following three specific aims: 1) Determine the cost-effectiveness of chemoprevention and the endoscopic management of Barrett's esophagus and associated dysplastic states. 2) Refine the model by enhancing specific data inputs to improve the accuracy of model predictions. 3) Determine the potential impact of risk stratification on the cost-effectiveness of chemoprevention and endoscopic surveillance and develop risk-stratified guidelines for Barrett's esophagus management. This research will provide much needed data to help establish management strategies for patients with Barrett's esophagus. Additionally, a group of mentors with expertise in oncology, gastroenterology, clinical research and decision analyses, as well as formal didactic training in outcomes research will provide the applicant with a firm basis to launch his career as a productive and independent clinical investigator.